The Reference Calibration kit is recommended for highest quality speaker measurements and is used for setting up PDC-2.6 HD, PDC-2.6P HD, HDP-3, HDP3-300 units.It includes:• DEQX measurement, analysis and correction software for PC• 5 meter USB cable to connect DEQX processor to PC• DEQX Calibrated™ Earthworks M30 measurement microphone• 5 meter balanced XLR microphone cableA boom microphone stand (not supplied) is required for speaker and room measurements. Stands are typically available for under $100 from a local musical instrument supply shop. • 1 x Calibrated Behringer ECM3000 balanced measurement microphone • 1 x 7-meter Professional Assembled Microphone Cable • 1 x 5-meter USB Cable • CD containing DEQX™ Calibration Software (DEQX-Cal) for use on Windows PC or laptop • DEQX Users and Installers Manual Click here to download a specification sheet for the HDP-3 Preamp Processor.Specifications subject to change without notice.